Up to now, as disclosed in, for example, patent literature No. 1, a technique has been known which reads version information on an application program installed on a terminal, and upgrades (updates) the application program on the basis of the version information.
Incidentally, in recent years, a cooperative application program is being considered which connects a communication device installed on, for example, a vehicle to a portable communication terminal carried by a user to enable a communication with each other, and allows the communication device and the portable communication terminal to execute a content in conjunction with each other. It is general that the cooperative application programs installed on the communication devices and the portable communication terminals are upgraded in the respective devices or the respective terminals, separately. In this case, since the portable communication terminals are carried by the users in use, the cooperative application program installed on each portable communication terminal can be frequently upgraded. However, because the communication device installed in the vehicle is not carried by the user in use, it is difficult to frequently upgrade the cooperative application program installed on the communication device. If a version of the cooperative application program installed on the communication device is not consistent with a version of the cooperative application program installed on the portable communication terminal (for example, a case in which the version of the cooperative application program of the communication device does not match with the version of the cooperative application program of the portable communication terminal, a case in which the cooperative application program of the communication device is not upgraded to a version corresponding to the cooperative application program of the portable communication terminal, etc.), there is the potential that the communication device and the portable communication terminal could not execute the content in cooperation with each other.